Enteric and Hepatitis Viruses in Clinical Practice
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Direct answer
A wheel-shaped virus seen by electron microscopy in infant stool — rotavirus — remains the leading cause of severe dehydrating diarrhoea in Indian children, and India answered it with ROTAVAC, the 116E-strain vaccine developed by Bharat Biotech and added to the universal immunisation programme. Norovirus now heads foodborne gastroenteritis across all ages. In hepatology, hepatitis A and E share the faecal-oral route and never chronify, but hepatitis E carries catastrophic fulminant risk in the third trimester of pregnancy; hepatitis B (a DNA virus with reverse transcriptase activity) and hepatitis C (an RNA flavivirus) chronify, cause cirrhosis and hepatocellular carcinoma, and are treated with tenofovir or entecavir for B and all-oral direct-acting antivirals for C — free of cost in India under the National Viral Hepatitis Control Programme since 2018.
What you must remember
- Rotavirus: double-stranded RNA, 11 segments, wheel-like morphology; NSP4 acts as a viral enterotoxin; diagnosis by stool antigen tests; ROTAVAC (116E strain, 3 oral doses at 6, 10, 14 weeks) sits in India's national schedule.
- Norovirus: low infectious dose, vomiting-predominant outbreaks in closed settings (cruises, weddings, schools); shellfish and food handlers are classic vehicles; no lasting immunity.
- Hepatitis A: incubation about four weeks; children asymptomatic, adults icteric; IgM anti-HAV confirms; no chronic state; inactivated vaccine for those who can afford it, while most Indian adults are already immune.
- Hepatitis E: the commonest cause of acute sporadic viral hepatitis in Indian adults; waterborne epidemics (the 1991 Kanpur outbreak with nearly 80,000 cases is the classic citation); fulminant hepatitis in late pregnancy with mortality up to 15-25%; no widely available vaccine in India.
- Hepatitis B markers: HBsAg (present in infection), HBeAg (high infectivity), IgM anti-HBc (acute — the only marker positive in the window period), anti-HBs (immunity); perinatal prophylaxis is vaccine plus immunoglobulin within 12 hours of birth.
- Hepatitis C: genotype 3 predominates in India; antibody screens, RNA confirms; pangenotypic sofosbuvir-velpatasvir for 12 weeks cures over 95%.
- Hepatitis D: defective circular RNA virus needing HBsAg to exist; superinfection of a chronic carrier causes the severest disease.
Reading a hepatitis panel line by line
A pregnant woman at 32 weeks has two weeks of jaundice, ALT above 1000 and prothrombin prolongation. IgM anti-HEV is positive: hepatitis E in the third trimester, the setting for fulminant hepatic failure — deliver in a centre with transplant capability. Had this been a mild illness in a child, IgM anti-HAV would have closed the case with reassurance.
Next, an antenatal HBsAg-positive woman with positive HBeAg and high DNA. Plan delivery in a centre that can give the baby hepatitis B immunoglobulin plus the first vaccine dose within 12 hours of birth (about 95% protective), and start or continue tenofovir in the mother from the second or third trimester to suppress viral load. Her own staging (fibrosis assessment, treatment indication) follows standard chronic hepatitis B pathways, remembering the phases — immune-tolerant HBeAg-positive with normal ALT, then immune-active hepatitis, then the HBeAg-negative chronic hepatitis that flares quietly.
Finally, a blood-donor screen shows anti-HCV reactivity. Confirm with RNA; if positive, genotype and assess fibrosis, then treat with a pangenotypic direct-acting regimen for 12 weeks. The Indian programme detail that changes practice: under the National Viral Hepatitis Control Programme, testing and direct-acting antivirals are provided free in government treatment centres, which removes cost as the reason for the historically low treatment uptake.
The window period trap
Between the disappearance of HBsAg and the appearance of anti-HBs lies the window, during which IgM anti-core antibody is the only positive marker — a single-question exam favourite. The same logic warns against interpreting isolated anti-HBc positivity (window, remote infection, or occult infection needing DNA testing) and explains why donor screening includes core antibody even when surface antigen is negative.
Frequently asked questions
Which rotavirus vaccine does India use and on what schedule?
ROTAVAC, the live attenuated monovalent human 116E strain vaccine developed indigenously by Bharat Biotech with Department of Biotechnology support, given orally in three doses at 6, 10 and 14 weeks within the universal immunisation programme.
Why is hepatitis E dangerous in pregnancy?
Third-trimester infection carries a substantial risk of fulminant hepatic failure with maternal and foetal mortality; the reason for the pregnancy-specific severity remains incompletely defined, so prevention rests on safe water.
What does an isolated IgM anti-HBc positivity mean?
Acute hepatitis B in the window period after HBsAg has cleared but before anti-HBs appears; alternatively remote infection — hepatitis B DNA testing resolves the ambiguity.
How is hepatitis C cured?
With direct-acting antivirals targeting NS3/4A protease, NS5A or NS5B polymerase — for example pangenotypic sofosbuvir-velpatasvir for 12 weeks — achieving sustained virological response above 95%, with India providing them free through the national programme.
Which enteric virus dominates infantile severe diarrhoea in India?
Rotavirus, ahead of norovirus, adenovirus types 40/41 and astrovirus; the introduction of rotavirus vaccination in Indian states has measurably reduced severe dehydrating episodes and related deaths.